fn main() {
    let x = 5;
    println!("The value of x is: {}", x);
    // x = 6;   //cannot assign twice to immutable variable
    // println!("The value of x is: {}", x);

    let mut y = 5;
    println!("The value of y is: {}", y);
    y = 6;
    println!("The value of y is: {}", y);

    let a = 5;
    let a = a + 1;
    let a = a * 2;
    println!("The value of x is: {0}", a);
}
